Native herbivore exerts contrasting effects on fire regime and vegetation structure

Abstract

Although native herbivores can alter fire regimes by consuming herbaceous vegetation that serves as fine fuel and, less commonly, accumulating fuel as nest material and other structures, simultaneous considerations of contrasting effects of herbivores on fire have scarcely been addressed. We proposed that a colonial rodent, vizcacha (Lagostomus maximus), reduces and increases fire intensity at different stages in its population cycle in the semiarid scrub of Argentina. Specifically, we hypothesized that, when colonies are active, vizcachas create natural fire-breaks through intense grazing, generating over time patches of large unburned shrubs in grazed zones. In contrast, when colonies are abandoned, recovery of fine fuels and previous accumulation of coarse wood on colonies during territorial displays increases fire intensity, creating patches of high shrub mortality.

Citation

Hierro, Jose L.; Clark, Kenneth L.; Branch, Lyn C.; Villarreal, Diego. 2011. Native herbivore exerts contrasting effects on fire regime and vegetation structure. Oecologia. 166(4): 1121-1129